Lens-grinding machine



1. SPAANDER.

LENS GRINDING MACHINE.

APPLICATION FILED MAY 1.1919.

Patented NW. 21, 1922,

; 9, vii

x INVENTOR Jfl/V SPAM/V0 5 I? TTORNEYS Patented Nov. 21, 1922.

entree. stares I l,d36,626 PATENT QFFIQE.

JAN SPAANDER, OF SOUTHZBRIDGE, MASSACHUSETTS ASSIGNOR-TO AMERICAN GPTIGAL COMPANY, OF SOUTHIBRIDGE, MASSACHUSETTS, A VOLUNTARY ASSOCIATION OF MASSACHUSETTS.

LENS-GRINDING MACHINE.

To all whom it may concern:

Be it known that 1, JAN SPAANDER, a subject of the Queen of Holland, residing at Southbridge, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Lens- Grinding Machines, of which the following is a specification.

' This invention relates to improvements in lo lens grinding machines and has particular reference to means for holding the lens during the grinding operation.

The leading object of the present invention is the provision of novel and improved means which will satisfactorily hold a lens for grinding without the use of pitch or other adhesives.

A further object of the present invention is the provision of an improved device particularly adapted for use in connection with a lens, one surface of which has already been prepared, which will automatically position the lens to control the presence or absence of prism in the finished product. I Other objects and advantages of my improved construction should be readily apparent by reference to the following specification taken in connection with the accompanying drawings, and it will be understood 80 that I may make-any modifications in the specific details of construction shown and described within the scope of the appended claims without departing from or exceeding the spirit of my invention. Figure I represents a vertical sectional view of my invention.

Figure II'represents a similar view of a slightly different form thereof.

Figure III represents a fragmentary plan view of the lens supporting table and adjusting device therefor.

In the drawings, the numeral 1 designates a lower grinding spindle of a lens grinding machine which is preferably adapted to be 415 rotated in any well known manner, although it will be understood that my invention is equally applicable for use in connection with a non-rotatable spindle or holder. The spindle is preferably provided with a laterally projectmg pin 2 adapted tobe engaged in the slot 3 in the mushroom shape body 4 of my invention, the member 4 in addition bein provided withthe conical socket 5 into whic the tapered upper end of the spindle 1 fits, the pinand slot engagement of the parts serving to secure them against relative rotation.

It will be noted that the body member 4 is exteriorly threaded as at 6 at the lower portion and above the threads is provided with the shoulder 7. Resting on this shoulder 7 are the lens clamping members 8 having the inwardly curved jaw portions 9 adapted to engage the edge of a lens blank 10. These clamping members have tapered outer faces 11 adaptedto be engaged by the interiorly tapered flange 12 of the nut 13 which is engzged on the threaded portion 6 of the memr 4 whereby upward screwing of this nut will Wedge or force the jaws inward into operative engagement with the lens blank, while reverse screwing will loosen them to permit of removal of the blank.

To satisfactorily retain the jaws in position I may make use of any suitable pivot or rocking connection between the jaws and the member 4, as for example the circumferential rib 14 on the member 4 fitting into the groove 15 of the jaw members, the rib6 providing a fulcrum on which the jaws swing.

To facilitate the employment of my construction if desired I may transversely bore the shank of the member 4 and place in this bore the spring 16 serving to normally press the jaws apart or into open position.

It will be noted that I have shown the upper faceof the member 4 in Figure II. as

possessing the same transverse curvature as I the blank 10 which is resting thereon. This is a decided advantage in the case of lenses which have been ground or finished on one side, in that they may be placed on the member 4 with their finished surface fitting tightly thereagainst and they will thus be accurately positioned withthe chord of their curve at right angles to the axis of the spindle 1 so that all possibility of prismatic grinding of the lens in finishing the second surface is eliminated.

As an alternative form of construction in place of a special curved up er surface on the member 4, I may either orm the member 4 with the upstanding annular flan 17 integral therewith or may form this ange separate from the member 4 and secure it thereto as by pivoting at 18, as illustrated in Figure III, or in any other desired manner. The advantage of making use of the annual flange is that it will accurately fit any spherical curve, either convex or concave and will re erl su ort it a ainst tilting relative to the axis of tiii d spindle 1. The form shown in Figure III ossesses an additional advanta e in that it is provided with the screw ad ustment 19 carried by the cross piece 20 connecting the sides of the flange and'bearin'g against the member 4, adjustment of this set screw lifting the flange member oiiz' 1ts normal seat 21 where it is in proper horlzontal position or at right angles to the axis of idea being that this tilting will cause a cor.-

responding tilting of the lens blank which will then have one side higher and one lower than the center causing a prismatic grindin of the final lens, as will be readily understood by those conversant-in the art. In this way I may absolutely control the amount of .prism to be ground on the lens without the difliculties usually'attendant upon prismatic blockin of the lens.

It Wll be understood that the ordinary tilting for prism variation is so slight that the jaws 9 will still properly engage and retain the blank 10 in position within the grinder.

From the foregoing description the con struction, operation and advantages of my improvement should be readily. apparent and it will be seen that I have provided anovel, simple and inexpensive construction by which a lens blank may be readily clampingly held in exactly correct position for grinding, eliminating the necessity of pitch or other adhesive and the possibility of breakingin either the mounting or detachment of the lens from the blank to which it has been secured by the adhesive and have also provided an improved construction particularly adaptable for use when prismatic value is to, be ground upon thelens.

I claim:

1. A deviceof the class described including a body portion having a supporting face upon which one surface of a lens blank is to be tightly fitted, lens clamping jaws fulcrumed on the body portion and provided with cam portions, a sleeve embracing the jaws, means for moving the sleeve over the cam portions of the jaws. to force the same 'into operative positionand means carried by the body portion and engaging the jaws for shifting the same into inoperative position. i

2. A device ofthe class described includ ing a rigidly supported body portion having a supporting face upon which one surface of a .lens blank is to be tightlyfitted, lens clampin jaws fulcrurned on the-body portion an provided w th cam portions, a

sleeve embracing the j aws, means for mov-' ing the sleeve over the cam portions of the jaws to force the same into operative position and means carried by the body portion and engaging the jaws for shifting the same into inoperative osition.

3. A; device 0 the character described,

comprising a socketed member having an exteriorly threa'ded lower portion surmounted by' lateral projections, jaw members mounted on the upper portion of said member and having recesses interlockin with said projections, said jaw members Iiaving tapered outer faces and terminatin in upper gri ping jaws, a nut mounts -on the threa edv portion having a' flange engagin the outer tapered faces'of the jaws where y' movement of the' nut in one direction cams the jaws to other about the projections of thesockete member as fulcrums,

and a supplemental rest in the form of anannulus pivoted to ,the, socketed member and disposed between the jaws to provide a rest for the lens. 7

4. A device of the character described, comprising a socketed member having an exteriorly threaded lower portion surmounted bg lateral projections, jaw members mounte on the upper portion of said member and having recesses interlocking with said'projections, said jaw members having. tapered outer faces and terminating in upper gripping jaws, a nut mounted on the threaded portion having a flange engaging the outer taipered faces of the jaws whereby movement 0 the ,nut in one direction camsthe jaws together about the rojections of the socketed member as in crums, a supplemental rest in the form of an annuluspivoted to the socketed'member and disposed between the jaws to provide a rest for the lens, and means for angularly adjusting said annulus to vary the relationship of a lens when positioned between the jaws.

5. A device of the character comprising a base portion, jaws fulcrumed on the base portion, means for swinging the jaws on their fulcrums to clampingly engage a lens therebetween, a lens rest in the form of an annulus pivotedto the base portion intermediate the jaws, means for swinging said rest on its pivot to vary the angle of a lens mounted between the jaws, and --means for indicating the angle to which said rest I described, 

